What is the most likely cause and appropriate management of cyclic pelvic pain in a 23‑year‑old woman with a 1.7 cm simple ovarian cyst and a copper intrauterine device?

Cyclic Pelvic Pain with Small Ovarian Cyst and Copper IUD

The most likely cause is primary dysmenorrhea exacerbated by the copper IUD, as the 1.7 cm simple ovarian cyst is physiologic and unrelated to her cyclic symptoms; management should focus on NSAIDs and consideration of IUD removal if pain persists despite medical therapy. 1, 2

Most Likely Diagnosis

Copper IUD-Related Dysmenorrhea

• Copper IUDs are well-established causes of increased menstrual pain and heavier bleeding, making this the primary suspect in a patient with cyclic pain and a nonhormonal IUD 2
• The 1.7 cm ovarian cyst is physiologically normal and functionally insignificant, as simple cysts less than 5 cm in premenopausal women typically resolve spontaneously and rarely cause symptoms 3
• Cyclic pain confined to the menstrual period (1-3 days) without progressive worsening suggests primary dysmenorrhea rather than secondary causes like endometriosis 1

Why the Cyst is NOT the Problem

• Simple ovarian cysts under 5 cm in reproductive-age women are functional and benign in approximately 999 out of 1,000 cases 3
• Functional cysts do not typically cause cyclic pain; they may cause acute pain only if they rupture or undergo torsion 3, 4
• The timing of pain (cyclic with menses) does not match the pattern expected from an ovarian cyst 2

Red Flags to Exclude Secondary Dysmenorrhea

Before accepting this as simple IUD-related dysmenorrhea, actively screen for these warning signs that would suggest endometriosis or other pathology 1:

• Progressive worsening of pain severity over months to years (not just since IUD placement)
• Pain extending beyond menstruation into other parts of the cycle
• Deep dyspareunia (pain with intercourse)
• Associated infertility concerns (affects 50% of endometriosis patients)
• Failure to respond to NSAIDs after 3-6 months of adequate trial
• Sacral backache specifically with menses

Management Algorithm

First-Line Treatment (No Further Imaging Needed)

• Trial of NSAIDs (ibuprofen or naproxen) starting 1-2 days before expected menses and continuing through the first 2-3 days of bleeding 2, 5
• The 1.7 cm simple cyst requires no intervention and no follow-up imaging unless it grows beyond 5 cm or becomes symptomatic with acute pain 3
• Reassure the patient that small functional cysts are normal ovarian physiology and not the source of cyclic pain 3

If NSAIDs Fail After 3-6 Months

• Consider copper IUD removal as the device itself is likely perpetuating the dysmenorrhea 2
• Transition to hormonal contraception (combined oral contraceptives or hormonal IUD) which treats dysmenorrhea effectively 5

When to Pursue Further Workup

Only pursue additional imaging or laparoscopy if 1, 6:

• Pain progressively worsens over time despite treatment
• Pain becomes non-cyclic or extends beyond menstruation
• Deep dyspareunia develops
• NSAIDs and hormonal therapy both fail after adequate trials
• Transvaginal ultrasound is the first-line imaging (not CT or MRI) if secondary causes need exclusion, with 82.5% sensitivity and 84.6% specificity for detecting endometriosis, adenomyosis, or other pathology 1, 6

Critical Pitfalls to Avoid

• Do not attribute cyclic pain to a small physiologic ovarian cyst—this leads to unnecessary interventions on benign findings 3
• Do not order CT imaging for cyclic pelvic pain in reproductive-age women—ultrasound is superior for gynecologic causes and avoids radiation exposure 7, 6
• Do not assume endometriosis without red flags—the majority of cyclic pain in young women with copper IUDs is primary dysmenorrhea exacerbated by the device 1, 2
• Do not perform diagnostic laparoscopy as a first-line test—it is invasive, requires anesthesia, and should only follow failed conservative management and inconclusive imaging 6